This invention relates to a device for protecting against jimmying of a door lock, and more particularly relates to a latch and lock guard to be secured externally to a door and door jamb to prevent or make more difficult illegal entry through that door.
It is well known that illegal entry into a door is often achieved by a burglar by sliding a plastic credit card or thin flat spring steel band into the latch and lock area of the door to release the latch or lock, or latch buttons. Alternatively, illegal entry into a door is oftentimes achieved by prying the door with a screwdriver or a wrecking bar with a sharpened point either in a vertical way, by prying under the door to lift the door and spring the lock, or by attacking the latch and lock directly to release it.
There have been numerous prior art proposals for anti-jimmy guards for doors. Typical of these is that described in Raccuglia U.S. Pat. No. 3,592,498 issued July 13, 1971, having a U-shaped bracket mounted on the inside surface of a door jamb to receive the extension of an L-shaped bracket mounted on the front of the door. When the door is in closed position, the screws holding the brackets in place are covered by the other bracket. While this device appears effective to prevent jimmying of the door with a credit card or the like, it does not appear intended to prevent jimmying of a door in a vertical direction. As well, when the door is in open position, the L-shaped bracket protrudes into the passage area.
Grinbaum U.S. Pat. No. 3,895,834 issued July 22, 1975, describes and illustrates a guard for a door employing a female member which mates with a male member, the members being secured to the door jamb and door respectively. The female member is an elongated bracket defining in cross-section the shape of an L with longitudinally spaced slots extending transversely through both surfaces defining the L. The male member is elongated and flat with longitudinally spaced elements extending across and engageable with the corresponding slots of the female member, each element defining a portion of a flat circular disc. The device in application requires mortising of the jamb to which the female member is secured, and carving in the jamb appropriate slots for receiving the elements of the male member. Thus, alignment of the two members is such that a skilled carpenter or cabinet maker would normally be required.
Wylie U.S. Pat. No. 2,454,904 issued Nov. 30, 1948 describes and illustrates a plate-like door lock protector again requiring mortising of the door and door jamb to which it is secured.
Other patents of general background interest are Canadian Pat. No. 1,055,547 of Rosenberg issued May 29, 1979; Canadian Pat. No. 1,082,249 of Rosenberg issued July 22, 1980; U.S. Pat. No. 3,271,063 of Garrett issued Sept. 6, 1966; U.S. Pat. No. 3,826,526 of Wepsala Jr. issued July 30, 1974; U.S. Pat. No. 3,761,119 of Bennett et al issued Sept. 25, 1973; U.S. Pat. No. 3,764,173 of Griffith issued Oct. 9, 1973; U.S. Pat. No. 4,178,027 of Charron issued Dec. 11, 1979; U.S. Pat. No. 2,484,024 of Garberding issued Oct. 11, 1949; U.S. Pat. No. 1,373,678 of Seimer issued Apr. 5, 1921 and Canadian Pat. No. 979,051 of Nemitz issued Dec. 2, 1975, all of these references describing various proposals for door lock or latch protectors.
It is an object of the present invention to provide a latch and lock guard for a door which is relatively easily manufactured and simple to install. It is a further object to provide such a device that may be easily installed on the outside of a door without mortising, and which will provide resistance against jimmying from the door in a direct face attack or in a vertical attack.